A. Technical Field
The present invention pertains generally to image processing, and relates more particularly to characterization of a droplet.
B. Background of the Invention
Printing technology is an important component of applications such as printed circuit board (hereafter, “PCB”) generation. Typically, PCB masks are printed by inkjet printers. It is important to be able to calibrate such printers as well as perform quality control in order to insure that their printing performance is consistent and meets specifications.
An inkjet printer head contains a set of nozzles. It is possible to characterize each nozzle's “signature” in terms of how it reproduces a calibration input pattern. One example of a calibration input pattern is a dot; a nozzle's rendering of the dot is a “droplet.” Major components of a nozzle's droplet signature include circularity, elongation, and splash.
Building a quantitative model of characteristics of a droplet signature is a valuable tool in managing the quality of devices that generate these droplets. For example, nozzle signature characterization can be used in a variety of quality control tests. A nozzle's output can be compared to its calibration signature in order to determine whether it has become clogged or is otherwise malfunctioning. In another example, two printer heads can be tested for compatibility by comparing the signatures of their nozzles and quantifying similarity or differences. This kind of test may be important for applications that require the use of multiple printer heads.
One skilled in the art will recognize the vast applicability of droplet, or other printed shape, characterization across numerous markets and devices.